fragments.  The reassembly queue must be reinitialized and the
   associated fragments abandoned whenever the REASSEMBLY TIMER expires,
   or a new datagram arrives carrying a FRAG field whose value is less
   than the highest FRAG value processed for this fragment sequence.
   The reassembly timer MUST be no less than 5 seconds.  It is
   recommended that fragmentation be avoided by applications wherever
   possible.

   Implementation of fragmentation is optional; an implementation that
   does not support fragmentation MUST drop any datagram whose FRAG
   field is other than X'00'.



RFC 1928                SOCKS Protocol Version 5              March 1996

   The programming interface for a SOCKS-aware UDP MUST report an
   available buffer space for UDP datagrams that is smaller than the
   actual space provided by the operating system:

          o  if ATYP is X'01' - 10+method_dependent octets smaller
          o  if ATYP is X'03' - 262+method_dependent octets smaller
          o  if ATYP is X'04' - 20+method_dependent octets smaller

8.  Security Considerations

   This document describes a protocol for the application-layer
   traversal of IP network firewalls.  The security of such traversal is
   highly dependent on the particular authentication and encapsulation
   methods provided in a particular implementation, and selected during
   negotiation between SOCKS client and SOCKS server.

   Careful consideration should be given by the administrator to the
   selection of authentication methods.

9.  References

   [1] Koblas, D., "SOCKS", Proceedings: 1992 Usenix Security Symposium.

Author's Address

       Marcus Leech
       Bell-Northern Research Ltd
       P.O. Box 3511, Stn. C,
       Ottawa, ON
       CANADA K1Y 4H7

       Phone: (613) 763-9145
       EMail: mleech@bnr.ca